Lubricant addition agents and lubricant compositions containing same



United States Patent Ofifice 3,232,874 Patented Feb. 1, 1966 3,232,874 LUBRICANT ADDITION AGENTS AND LUBRI- CANT COMPOSITIONS CONTAINING SAD [E Helen Sellei Beretvas, Chicago, Ill., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Filed Feb. 20, 1961, Ser. No. 90,191 3 Claims. (Cl. 25237.2)

This invention relates to a new and useful combination of zinc naphthenate and alkylene oxide-resin amine reaction product rust inhibitors. This invention further relates to lubricants of improved anti-rust properties obtained by incorporation of a small amount of the combi nation in the lubricant. Anti-rust or rust preventative properties are important attributes of most lubricants including engine oils, greases, gear oils and turbine oils. As a consequence, a wide variety and great number of additives have been proposed or used for the purpose of imparting anti-rust properties to lubricants. Although the uses of zinc naphthenate or certain alkylene oxide amines'separately have been proposed, insofar as I know, a combination of zinc naphthenate with alkylene oxideresin amines has not been proposed or tested for value in oils. I have now found that the combination is surprisingly'effective in imparting anti-rust properties to lubricants. For example, I have found that the combination is more eifective than either zinc naphthenate or the alkylene ox de-resin amine alone.

In the practice of the invention, a combination of Zinc naphthenate and an alkylene oxide-resin amine is provided. The combination or mixture of ingredients is useful as a rust inhibitor in a lubricant in a small amount, e.g. from about 0.25 to about 20 weight percent, to impart improved anti-rust properties to the lubricant.

Although the proportions of each ingredient of the mixture, or combination of ingredients of this invention may be varied by those skilled in the art for particular purposes, it is advantageous that the weight ratio of zinc naphethenatezalkylene oxide-resin amine be in the range of from 100:1 to 1:2 and preferably in the range of 40:1 to 5:1; I

The additive combination of this invention can be used in a number of lubricating applications. It may be incorporated as an anti-rust agent in crankcase lubricating oils for internal combustion engines. The additive combination also is useful in a variety of lubricants and viscous oil compositions as rust preventatives, for example, in turbine oil, cutting oil and grease formulations. The concentration level depends upon the intended use environment and to some extent on the solubility of the phosphonic mono-esters in the hydrocarbon base oil. Solubility may be improved by dissolving the additives in carrier solvents such as benzene, toluene, xylenes and higher aromatics, low molecular weight alcohols, and the like, in order to facilitate incorporation in the base lubricant. been conventionally or solvent refined and may vary widely .in viscosity range and other properties such as pour point, flash, etc. The finished blend ordinarily will contain other additives such as oxidation inhibitors, pour depressants, anti-foam agents, thickening agents, and the like. Thickening agents may be present in" amounts known to the art to be sufiicient to thicken normally liquid oils to I grease consistency. Examples of such thickeners arethe aryl substituted ureas, mahogany soaps-and lower molecular weight calcium soaps, lithium soaps such'as lithium stearate or l2-hydroxy stearate, etc.

In a preferred use, the rust inhibitor combination is incorporated into a bearing lubricant such as a lubricating oil or grease. The combination, in such preferred use, is especially effective in preventing black discoloration of bearing surfaces as well as formation of reddish-brown The base lubricant may be an oil which has specks normally characteristic of rust. The black discoloration is apparently the manifestation of an etching acidic attack on the bearings and is, therefore, corrosion rather than true rust. The acidic substances causing the discoloration are believed to be produced by oxidative deterioration of greases and oils, particularly at high temperatures normally encountered at bearing surfaces. The combination of this invention is effective in inhibiting such corrosion of bearings in addition to inhibiting formation of rust. The added corrosion inhibiting effect also indirectly serves to further inhibit rusting in that rusting is believed to be more prevalent at the corrosion sites identified by the black discoloration. In the preferred use in bearing lubricants the amounts of additive used may be selected with regard to the intended use, taking into account such factors as total bearing surfaces, loads, surface temperatures to be encountered, e.g. from friction, and other factors. However, in bearing lubricants such as lubricating oils and greases, it is advantageous to include at least 0.2 and preferably 0.5 to 3 weight percent of the additive combination.

In another preferred use, the additive combination of this invention is used in internal combustion engine lubricating oils in the amounts described above and more advantageously in an amount of from 0.5 to 3 weight percent. Such lubricating oils include the mineral lubricating oils as well as other hydrocarbon oils both natural and synthetic, for example, those obtained by polymerization of olefins. The lubricating oil may also be those synthetic lubricating oils of the alkylene oxide type and the monoand polycarboxylic acid ester-type, e.g. the oil-soluble esters of adipic acid, sebacic acid, azelaic acid, etc. It is also contemplated that various other well known addition agents such as anti-oxidants, anti-foaming agents, pour point depressants, extreme pressure agents, antiwear agents, dispersance or detergency agents, corrosion inhibitors, and the like or even additional rust inhibitors, e.g. 13% calcium sulfonate, may be incorporated in the lubricating oils containing the rust inhibiting ingredients of the present invention. The lubricating oils may be any such lubricating oils as described above but are not limited thereto. Lubricating oils containing the rust inhibiting ingredients of this invention are especially useful when incorporated in a drive-away lubricating oil (i.e., break-in oil or initial fill oil used in new engines). Such drive-away oils usually have an SAE grade in the range of S to 40. I

After assembly in an automobile, a new engine is usually started and the automobile is driven a short distance and permitted to stand for a period of time. The engine is intermittently started for very short periods and stopped for very long periods throughout delivery of the automobile. Under such conditions, the engine is very susceptible to rusting, especially at corrosion sites apparently created by erosion of ferrous surfaces by acids introduced into and accumulated in the crankcase or oil reservoir from the combustion chamber by blow-by. Where such sites .are created on ferrous metal surfaces, the eroded surfaces apparently become more susceptible to rust caused by the presence of water and oxygen. In lowspeed short-time operation of an internal combustion engine, the accumulation of acids and water is increased and, it follows, the corrosion sites andrust at such corrosion sites are also increased. It has long been known that the lubricating oil alone is not sufiicient to prevent rusting; this is particularly so with accelerated rusting at corrosion sites. The addition agents of this invention are especially useful in inhibiting rusting due to the presence of oxygen and water at such corrosion sites. For any given use of the additives in lubricants, concentrates of the mixture of ingredients are also intended; such concentrates may contain the mixture of ingredients alone or in combination with other additives, in amounts of from about 10 to 100 and preferably 30 to 70 weight percent, e.g. in suitable solvent such as a hydrocarbon, a low molecular weight chlorinated hydrocarbon, a monoalkyl ether of a glycol, e.g. Cellosolve, etc.

The alkylene oxide-resin amines used herein are resin amine-alkylene oxide reaction products. The resin amines may be prepared by the reaction of stabilized gum and wood resins with ammonia followed by catalytic hydrogenation at elevated pressure and temperature. The preparation is well known to the art. The resin amines may contain both abietie-type amines and pimaric-type amines. The abietic-type amines include abietyl amines, levopimaryl amine, neoabietyl amine, dehydroabietyl amine, dihydroabietyl amine and tetraabietyl amine. The pimarictype amines include dextropimaryl amine and isodextropimaryl amine. The alkylene oxide-resin amines may be formed by the reaction of from 1 to 50 and preferably from 2 to 10 moles of a 2 to 3 carbon atom alkylene oxide, i.e., either ethylene oxide or propylene oxide with resin amine. The alkylene oxide-resin amines are believed to correspond to the formula wherein R is the residue of a resin amine, e.g. an abietyl group, n is an integer of 2 to 3, x is to 1, y is 0 to about 50 and preferably 1 to 9, z is 1 to 2 and the sum of x plus 2 is 2.

The alkylene oxide-resin amines may be purchased if desired as commercial products. Examples of such commercial products are the alkylene oxide-resin amines marketed under the trade name Polyrad by Hercules Powder Company. Such commercial alkylene oxideresin amines vary in the alkylene oxide content apparently from less than one (on the average) to over 50 reacted alkylene oxide groups per average molecule. The Polyrads are ethylene oxide-resin amine reaction products. The resin amine used in their preparation predominates in abietyl amines such as dehydroabietyl amine and tetraabietyl amine. Alkylene oxide-resin amines are marketed in concentrated form and in alcoholic solvent and may be used in either form. The alkylene oxide-resin amines are normally solid and can be dissolved in alcohol if desired or can be utilized without solution in combination with the acylsarcosine and imidazoline for use in lubricating oils. An example of the Polyrads is Polyrad 0515A which evidently has an average of about 3.6 reacted alkylene oxide groups per molecule calculated from nitrogen content. 1

EXAMPLE OF RUST INHIBITION In order to demonstrate the utility of the mixture of ingredients of this invention, Samples A through D were prepared as identified below and were tested in accordance with a Modified HBr Emulsion Test. In accordance with that test, one inch by one inch polished steel squares were immersed in a emulsion of 0.24% HBr in solvent extracted SAE 50 mineral lubricating oil for one minute. The steel squares were then removed and suspended in the laboratory and exposed to the atmosphere for one minute. An exposed square was then dipped in each of Samples A through D ten times within a period of one minute. The dipped squares were then suspended in the laboratory exposed to the atmosphere for two hours. The exposed squares were then placed in a humidity cabinet for 16 hours at 100% relative humidity and 100 F. After 16 hours, the squares were removed from the humidity cabinet and examined for percent of surface rusted. The result for each sample of oil tested is reported in Table I;

Sample AAn SAE 10 hydrocarbon lubricating oil containing 2.2 vol. percent of a metal neutralized phosphorus sulfide-hydrocarbon reaction product (detergency additive) and about 1.1 volume percent of a zinc dialkyl dithiophosphate (corrosion and oxidation inhibitor).

Sample B-Sample A containing 0.1% of Polyrad 0515A.

Sample C-Sample A containing 1.0% zinc naphthenate.

Sample D-Sample A containing 0.1% of Polyrad 0515A and 1.0% zinc naphthenate.

Table 1 Sample: Percent surface rusted A to B 90 to 100 C 65 to 80 D 3 to 5 With reference to the data reported above in Table I, it is seen that neither the alkylene oxide-resin amine (Polyrad 0515A) of Sample B nor the zinc naphthenate of Sample C markedly improved rust protection in the lubricating oil. However, the combination of alkylene oxide-resin amine and zinc naphthenate gave almost complete protection under the test conditions.

It is evident from the above that I have provided a new and improved rust inhibitor composition which is useful as a lubricant addition agent.

I claim:

1. A lubricant composition consisting essentially of a major amount of a hydrocarbon lubricating oil and about 0.25-20 wt. percent of a mixture of zinc naphthenate and an ethylene oxide-resin amine reaction product formed by reacting 2-10 moles of an ethylene oxide with resin amine, said zinc naphenate and said ethylene oxide-resin amine reaction product being present in said mixture in a wt. ratio in the range of from 40:1 to 5:1.

2. A lubricating oil addition agent concentrate consisting essentially of from 30 to 70 wt. percent hydrocarbon oil and from 30 to 70 wt. percent of the rust inhibiting composition of claim 1, said concentrate being capable of dilution with a normally liquid lubricating oil to form a rust inhibited lubricant composition containing from about 0.25 to about 20 percent of said rust inhibiting composition.

3. A lubricant composition consisting essentially of a normally liquid hydrocarbon lubricating oil containing from 0.5 to 3 weight percent of a mixture of zinc naphthenate and an ethylene oxide-resin amine reaction prod uct having an average of about 3.6 reacted ethylene oxide groups per molecule, the weight ratio of said zinc naphthenate to said ethylene oxide-resin amine being about 10:1.

References Cited by the Examiner UNITED STATES PATENTS 2,194,429 3/1940 Krzikalla et al 260-100 2,510,063 6/1950 Bried 252392 X 2,830,951 4/1958 Bowden et a1 25237.2 2,856,299 10/1958 Westlund 252-390 X OTHER REFERENCES Haynes: Chemical Trade Names and Commercial Synonyms, 1955, page 338.

DANIEL E. WYMAN, Primary Examiner.

JULIUS GREENWALD, ALPHONSO D. SULLIVAN,

Examiners.

1 Zn in zinc naphthenate: 14.5%. 

1. A LUBRICANT COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR AMOUNT OF A HYDROCARBON LUBRICATING OIL AND ABOAUT 0.25-20 WT. PERCENT OF A MIXTURE OF ZINC NAPHTHENATE AND AN ETHYLENE OXIDE-RESIN AMINE REACTION PRODUCT FORMED BY REACTING 2-10 MOLES OF AN ETHYLENE OXIDE WITH RESIN AMINE, SAID ZINC NAPHENATE AND SAID ETHYLENE OXIDE-RESIN AMINE REACTION PRODUCT BEING PRESENT IN SAID MIXTURE IN A WT. RATIO IN THE RANGE OF FROM 40:1 TO 5:1. 